Technical Field
The present disclosure relates generally to a location information system and a method of controlling the same and, more particularly, to a location information system that acquires corrected information about a current position and heading of a vehicle when a navigation function of a smart device is used in the vehicle.
Discussion of the Related Art
Interconnection technology between smart devices such as smartphones and vehicles has increased as use of smart devices has become more widespread. To this end, standardization organizations and mobile providers are proposing various technologies. Examples of such standard technology can include “MirrorLink” which is standardized through the Car Connectivity Consortium (CCC), “Apple CarPlay” of Apple, and “Android Auto” of Google. Data exchange according to such technologies will now be described with reference to FIG. 1.
FIG. 1 illustrates an example of data exchange through link between a vehicle and a smartphone.
As shown in FIG. 1, a communication module 11 of a vehicle head unit terminal 10 can perform data exchange through a link to a communication module 21 of a smartphone 20 in a wired/wireless manner (e.g., universal serial bus (USB) or Wi-Fi). Specifically, the smartphone 20 creates video and audio information, streams the created information to the vehicle, decodes streams received from the vehicle head unit terminal 10, displays images through a display such as an LCD, and outputs sound through a sound system set in the vehicle. In addition, information of the vehicle and the smartphone may be exchanged through a data channel.
Since such vehicle and smartphone interconnection technology can make up for the weakness of vehicle IT by integrating rapidly improved smartphone technology into the automobile industry with relatively slow technological innovation, many vehicle manufacturers are expected to apply the interconnection technology to mass production for the foreseeable future. For example, a navigation application can rely on interconnection standard technology between a vehicle and the smartphone. In this regard, it is important for the navigation application to acquire correct location information for correct navigation operation.
A smartphone includes a sensor and an algorithm for estimating correct location information by combining location information acquired through a global positioning system (GPS), Wi-Fi, a mobile network and the like. However, when the smartphone operates in a vehicle, it may be difficult to acquire location information through a GPS module and Wi-Fi. Accordingly, technical standards propose schemes for transmitting location information acquired through a high-performance GPS module built in a vehicle to a smartphone such that the smartphone estimates current location on the basis of the location information. However, since a GPS module built in a vehicle is relatively expensive and requires a separate antenna, housing, high-performance coaxial cable and the like, a vehicle that is not provided with an embedded navigation system of a vehicle manufacturer is not equipped with the GPS module in general.
Accordingly, if location information is acquired using only a GPS module of a smartphone inside of such vehicle, it is difficult to track information about a direction in which the vehicle current travels at a low speed, i.e., heading information. Heading information is typically acquired by comparing GPS coordinates measured at two or more different times and can refer to a direction of the next coordinate on the basis of the previous coordinates. This is described with reference to FIGS. 2A and 2B.
FIGS. 2A and 2B illustrate problems that may be generated when a normal smartphone acquires heading information when a vehicle travels at a low speed.
Generally, when location information is acquired using a GPS module of a conventional smartphone in the vehicle 100, the location information error amounts to a 2 to 3-meter radius. When the location error sensed through the GPS module is generated in front of or behind the vehicle 100, the error can be considered to hardly affect the heading information. However, if the location error is generated at the sides of the vehicle, a large error may be generated in the heading information, particularly when the vehicle travels at a low speed.
For example, when the vehicle travels at a high speed, as shown in FIG. 2A, if the location of the vehicle 100 leaning to one side within an error radius is sensed before the vehicle moves, and location of the vehicle leaning to the other side within the error radium is sensed after moving, there is little difference between a heading error range 219 and actual heading 220. However, when the vehicle 100 travels at a low speed, as shown in FIG. 2B, a maximum lateral error range 210′ may considerably differ from the actual heading 200.
In addition, the reliability of smartphone location information decreases in a GPS shadow area even though the smartphone has components for locating a vehicle in the shadow area, such as a gyroscope. This is because it is difficult for the gyroscope, which operates under the condition that the smartphone is mounted at a predetermined angle, to estimate the correct location since the user places the smartphone inside the vehicle arbitrarily.